47i Mr. R. C. Wrougliton 07i 



constitutional feature of the species, but rather one dependent 

 upon some peculiarity of position or structure of the individual 



P^'^'P- .... 



In his preliminary notice Krempf is unable to assloju to 



the organs any definite function in the physiology of the 



polyps. He shows the close histological resemblance which 



they bear to the greatly thickened endoderm occurring in the 



deeper regions of the polyp, a resemblance to whicli allusion 



has already been made. To my mind the histological 



characters are such as to point to the tissue being mainly 



inactive. The small nuclei, meagre amount of protoplasm, 



and great vacuolization do not suggest a piiysiologically 



active tissue. This is the conclusion to whicli I have come 



with regard to the hypertrophied endoderm in the deeper 



regions of coral polyps generally, and I do not see that any 



other conclusion is to be reached with regard to the greatly 



thickened endoderm of the tentacular downgrowths. In the 



deeper regions of the polyps little or no growth is going on, 



mesenteries are absent, and the thickened tissue there 



probably serves to diminish the polypal cavity, so that the 



circulation of the internal nutritive fluid is more restricted to 



the upper regions, where growth is in actual progress. If 



we consider that the formation of the downgrowths is 



dependent upon mechanical influences, it is manifest that we 



need not necessarily assign to them any particular role in the 



economy of the polyp. 



In correspondence with M. Krempf he informs me that he 



hopes to show later that the invaginations contain reserve food 



material and that they serve to nourish the young embryos. 



In this connexion it may be mentioned that none of the 



polyps of Pocillopora examined by me contained any sexual 



cells or embryos, and none of the staining reagents employed 



indicated the presence of reserve food material. 



LXIV. — Notes on the Genus Tatera, ivilh Descriptions of new 

 Species. By R. C. Wroughton. 



In studying a small collection of mammals from West Africa 

 nny attention was called to the genus Tatera, which I found 

 to be represented in the British Museum Collection by a 

 considerable number of specimens. On collating and com- 

 paring these I discovered that^ though there were apparently 

 a great number of quite easily distinguishable forms, the 



